De Jong had joined Gladbach from FC Twente in 2012 but struggled to make an impact in the Bundesliga. He was allowed to join Newcastle on loan in January but was unable to score in 12 appearances.

Gladbach sporting director Max Eberl added on the Bundesliga club's site: "Eindhoven wanted to sign Luuk by all means, and we were able to reach an agreement for this transfer. We wish Luuk all the best for his future."